Start by replacing the FPR-fuel pressure regulator if you have a very old unit or unknown.
If you still hear the whine, it will be the old fuel pump.
If you put in a new fuel pump, you need to replace the strainer, seal and fuel filter or the possibility of a torn fuel strainer could put junk thru the new fuel pump.
On a budget, you might try ebay or I use larts for "good used"
larts_porsche_parts on eBay
GL
J_AZ